Electrospray Mass Spectrometric Studies of Two Palladium-Allyl Complexes of the Trost Standard Ligand

Two allyl-palladium(II) complexes bearing the Trost standard ligand (1), i.e., [(C3H5)Pd(S,S-1)]+CF3-SO3- and [(c-C6H9)Pd(S,S-1)]+BArF- (BArF- = [B((3,5-(CF3)(2))C6H3)(4)](-)), are investigated using electrospray ionization (ESI) mass spectrometry. Both species form abundant quasi-molecular ions [(C3H5)Pd(S,S-1)](+) and [(c-C6H9)Pd(S,S-1)](+), respectively. At elevated concentrations of the solutions admitted to the ESI source, significant aggregation to binuclear species is observed, which agrees with recent results from solution chemistry. Consistent with solution-phase studies, the tendency of clustering is much less pronounced for the bulky BArF- counterion compared to the smaller Inflate.